Wireless communication networks divide a coverage area into multiple cells each arranged to communicate with mobile stations (e.g., mobile phones) with minimal interference between the cells. A mobile station crossing the coverage area has its communications handed-off between adjacent cells. Each of the multiple cells is typically served by a base station having a transceiver that communicates with the mobile station via an antenna situated on a tower.
Tower-mounted amplifiers (TMA's) used with the base station antenna improve the sensitivity of base station with respect to amplifier systems located at the base of the tower. Signals received by the antenna are amplified by the TMA before being transmitted over a transmission line to a radio of the base station. As a result, the signal-to-noise ratio of the signal communicated to the radio is preserved as the line losses reduce the level of the amplified signal transmitted to the radio. Preserving the signal-to-noise ratio also reduces the number of base stations required to cover a given coverage area by extending their range.
To optimize sensitivity and improve performance of the TMA, it is desirable that its low-noise amplifier transistor have a minimized noise figure. A conventional approach for enhancing the performance of heat-sensitive electronic equipment, such as low-noise amplifier transistors, is to cool the components of the equipment using a thermoelectric cooler. Thermoelectric coolers constitute solid state heat pumps that may be used to extract heat from electronic equipment. Often, a thermoelectric cooler includes a cold side that is placed in heat transfer communication with the chassis or housing of a complete electronic device, a hot side from which transferred heat is dissipated, and a thermoelectric module that transfers heat from the cold side to the hot side.
This conventional approach for reducing the operating temperature of electronic devices suffers from certain deficiencies. In many conventional arrangements, the thermoelectric cooler must cool an enclosure housing the electronic device and various heat-generating components inside the enclosure. For example, a TMA incorporates heat-generating components, such as filters, in addition to the low-noise amplifier transistor of the TMA. As a result, the cooling capacity of the thermoelectric cooler must accommodate heat generated by components of the TMA in addition to the heat generated by the low-noise amplifier transistor. Increasing the required cooling capacity of the thermoelectric cooler increases its cost and also increases the electrical power required to operate the thermoelectric cooler. Moreover, a ventilation fan may be required to convectively cool a heat sink thermally coupled with the hot side of the thermoelectric cooler.
Therefore, it would be desirable, among other things, to address cooling issues associates with TMAs and to reduce the cooling capacity of a thermoelectric cooler used to reduce the operating temperature of low-noise amplifier transistors used in wireless communications networks.